Pneumatic hammer.



H. KELLER. PNEUMATIO HAMMER. APPLIOATION 'I'ILED-OOT. 22, 190 8.

' .Patented Aug. 13,1912.

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HARRY KELLER, OF PHILADELPHIA, PENNSYLVANIA.

PNEUMATIC HAMMER.

Specification of Letters Patent.

Patented Auw. 13, 1912.

Application filed October 22, 1908. Serial No. 459,075.

To all whom t may concern:

Be itknown that I, HARRY KELLER, a citizen of the United States, residing in the city and county of Philadelphia, State of 5 Pennsylvania, have invented a new and useiful Pneumatic Hammer, of which the tollowing is a specification.

The objectiotl my present invention is to design' a pneumatic tool wherein I am enabled to eliminate the delicate and intri cate parts, the lifefof which are comparatively short and which are expensive to replace, and I employ in lieu thereof a simplified construction which gives in practice the highest possible etliciency without the very objectionable feature ot such parts becoming so worn that it is necessary to replace the same within a short period ot' time.

To the above ends my invention consists Vot' a novel construction of a pneumatic tool in which the handle or cylinder head is tastened to the cylinder' by means of a tapered thread which, in conjunction with a-spring box and spring interposed between the handle or valve box, enables me to dispense With the clamping devices, which have heretofore been deemed essential irt devices of this character.

It further consists oit a novel construction of a pneumatic tool wherein the valve casing is maintained in position against the cylinder by means of a novel 4construction otl a resilient' casing, wherebyv an air-tight connection between the valve casing and the cylinder is maintainedat all times and after the handle has been secured in assembled position, owing to the provision ot `the vtapered thread in theV head block thereof, there will always be a rigid air-tight connection between such head block and the y cylinderland the constant wear of the threads and the loosening of the head block from the cylinder, thereby permitting the motive fluid to escape, is positively prevented.

'It further consists of a novel construction of a differential piston having a constant pressure onl the smaller diti'erential area and a yvarying 'pressure on lthe larger pressurearea, whereby there is never at any time any pressure on the striking oint of the piston or the working tool, and t e ports and passages at-the frontor forward endv of the piston chamber exhaust directly into the atmosphere.

It further consists of a novel construction of a distributing valve having dilferential pressure area with constant'pressure of the motive fluid on the smaller area and an intermittent pressure of the motivo fluid on the larger area, thereby assuring a'positive movement of the valve and the accurate c011- trol o'i the reciprocating piston.

It further consists of other novel features otl construction, all as will be hereinafter fully set forth. l

For the purpose of illustrating my invention I have shown in the present instance but one form thereof, since thesame has been found in practice to give satisfactory and reliable results, and is at present preferred by me, although it is to be understood that the various instrunientalities of which my invention consists can be variously arranged and organized and that my invention is not limited to the precise ar rangement and organization of these instrumentalities as herein set forth.

Figure l represents a lcngitudinal sectional view of a pneumatictool embodying my invention. Fig, 2 represents a sectional view ot Fig. l, the handleand the retaining device for the valve casing having been removed. Fig. 3 representsv a perspective view ot' the valve in detached position. Fig. 4: represents a longitudinal section of Fig. 3. Fig. 5 represents an end view of thevalve. Fig. 6 represents a sectional viewon line -zu, Fig. 2. Fig. 7 represents a longtudif nal section of another embodiment ofmy invention, the same type of piston and valve being employed, certain other details o f the construction being slightly l modified to adapt the tool for different kinds of work.A

Similar numerals of reference indicate corresponding parts .in the figures.

Referring to thel drawings :`-In all the embodiments of my invention, as herein i a head block 9 having a tapered thread 10, Which engagesvvith a similar tapered thread of the cylinder 1, in order to 'secure the arts in assembled position. The motive uid, Which Would preferably be compressed air,

enters the vhandle through the passage 11,

which isv controlled by means of the manually actuated throttlmg device 12 Aof any` terial 17, Which'is maintained in engagementwith the Walls of the chamber 15 owing to the pressure of the motive' fluid passing through the ports 18, which communicate With the interior'of the casing 13 and With the annular groove 16, it being seen that a spring 19 abuts against the inner end of the chamber 15 Aand against the bottomof the casing 13, thereby causing said casing to be firmly seated againstI thevalve box 20 and causingthe movable bottom 21 thereof to abut against the inner end of the cylinder 1 and form an air-tight connection at such point When the part-s are linassembled position, as Will be evident from Fig. 1.

When the parts are in the position seen in Fig. 1, the piston is in extreme rearward position and the valve 22 has a constant pressure on its small head 23 and since there is no pressure on the larger head 24, the valve will be seated in the position 'seen in Fig. 1. The valve 22, in the present' instance, is closed at one end as indicated at .25, and isprovided with an annular groove 26 at its closed end, it being s'een that the heads 23 and 24 are joined by a neck 27 and the closed end 25 is preferably rounded, as most clearly seen in Figs. 2 .and 4. The smaller diameter I23 of the'valve isada ted to travel in the smaller diameter 28 o the valve box20 While the enlar ed diameter 2 4 is adapted to travel in the en arged diameter 29 of the valve'box 20, it being noted that the motive fluid has free access to vthe distributing chamber 14. When the parts are in the' position seen in Fig. 1, the motive fluid may pass through ports 30 into the passages 31, Which open into the enlarged piston chamber 2 and acting against the enlarged head 5 of the piston 4 will cause the same to be moved forwardly into the position seen in Fig. 2 and a blow Will be im'- parted to the reduced end 32 of the plunger 33 and cause the latter to impart a blow to the shank of the working tool 34, which extends through the aperuwed vbushing 35, which has preferably a driving fit in the end 36 of the cylinder 1, it being, seen that the enlarged head 37 of the lunger 33 moves Within-a chamber 38 Whic is preferably of a different diameter than the aperture 36. If desired the plunger 33 may be dispensed With and the piston will impart its blow di- ,Y

-rectly to the Working tool.

of the valve A22 Will cause the valve to as'-` s-ume the position seen in Fig. 2, at which time'the smallerhead 23Will prevent the motive fluid passing from the distributing chamber14 to the port 30, as Will be under-y stood by reference to Fig. 2 and the motive fluid may exhaust through ports 48 into which latter the passages'41. discharge.

The motive fluid Within the valve casing may exhaust through the passages 31 ports 30 and ports 48 to the atmosphere.

The piston is returned to its rearward position, as seen in Fig. ,1 owing to the pressurefof the motive fluid lagainst the shoulder formed by the groove 7 of the enlarged head 5. As soon as the front end ot the piston uncovers the port 49 the pressure under the -valve acting against the larger head 24 thereof will be released through the port 47, passage 46, port 49, piston chamber 3, port 39, passa ges 40 and 41, thence through the main exhaust ports 48 to theatmosphere andthe constant pressure on the smaller head 23 of the valve Will cause said valve to be seated in its forward position. It will be noted that there is always a constant pressure of live motive fluid through port 42, passage 43 and port 44.

' In the embodiment seen in Fig. 7, I have shown a construction wherein the Working tool is of the spindle type, the piston impartingv itsblovv directly thereagainst, but I do not desire to belimited toany particular construction of the Working tool, since the form of such tool varies in practice in accordance with the Workwhich istto'be accomplished. In this embodiment,.the ports and passages are similar to those already described -With respect to Figs. 1 to 6 inclusive and I also employ a differential piston and a differential valve,'th e construction of which corresponds to that seen in said ligures except' that the saine is constructed upon a larger scale. In this embodiment, 50 designates a cylinder provided with the differential diameters 51 and 52, within which the heads 53 and 54 of the piston 55 fare adapted to reciprocate, said heads 53 and 54 being connected by the neck 56. The shank deemed it unnecessary to further describe- 'of the Working tool 57 extends directly into the forward end of-the chamber 52 so that the pistonvwill impact' directly thercagainst,

and a free exhaust port 58 to the atmos phere is provided at the forward end ot' the chamber 52. 'designates a cylinder head clamping ring 63 having a lug 64 adapted toy be seated in a recess 65 in said cylinder head 59, said clamping ring 63 being maintained in assembled position by means of a suitable fastening device 66 of the usual construction. Since the operation of this embodiment et my invention is similar to that already described and since the construction of the ports and passages and 'of the piston and differential valve 67 is the same, I have the same.

I wish to call particular attention to the manner in which the valve'casing isangularly recessed in proximity to-the portsSO, since by such a construction the passages through the valvd casing may be readily drilledin such a manner that there are no extra holes or passages through the casing which require plugging, as is necessary in the usual construction of such casings, and thereby I am enabled to eliminatev the liability of such plugs Werking loose due to thef excessive vibration, with consequent leakage of the motive fluid and loss of power in the pneumatic tool.

Having thus described my invention, what I claim as new and desire to secure by Let-- ters Patent, is

1. In a pneumatic tool, the combination with a cylinder having a tapered thread, of a handle having a recessed head block engaging said thread, a valve box within said head block, and a spring pressed casing intermediate said valve box and one end of said recess.

2. In a pneumatic tool, the combination with a cylinder having a tapered thread, of aI handle engaging said thread, a valve box within said handle, a spring pressed casing for maintaining said valve box against said cylinder, and packing carried by said casing.

3.- In a pneumatic tool, the con'ib'ination with a cylinder' having a tapered thread, of a handle engaging said thread, a valve box 'withinsaid handle, a spring pressed casing for maintainingsaid valve box against said cylinder, packing carried by said casing, and means for conducting motive fluid to said packing.

4. In a pneumatic tool, the combinationl with a cylinder having a tapered thread, of a handle having ahead block engaging said thread, said head block being recessed, a valve box within said recess, a'hollow casinff Within said recess intermediate said boxanc ne end of said recess, packing carried by said casing and engaging the walls of said recess, means for conducting motive Huid to said packing, and resilient means co-act'- ing with said casing for holding said valve boxin air tight engagementwith said cylinder. r

5. In a pneumatic tool, the combination with a cylinder having a tapered thread, of

a handle having a head block engaging said thread, said head block having a recess therein to which motive luidis admitted, l

a valve box within said recess, a hollow cas.

ing contiguous said valve-box and provided with an external groove having portscom- .municating therewith and with the interior in said groove, and

of said casing,'packin` casing and one end a spring engaging sai of said recess.

6. In a pneumatic' tool, thel combination 'with a cylinder having a tapered thread, of a handle having an apertured block engaging said thread, said head' block having a ditferential bore to which. motive fiuid is admitted, 'a valve box Within oneof said diameters, an apertured casing in the other ot said diameters and engaging said valve box, said casing being provided with pacl ing on its periphery, means for admitting motive fluid to said packing,l and a spring' engaging said casing `and causing the latter to maintain said valve box in air tight engagement with the end of said cylinder.

HARRY KELLER.

Witnesses:

H. S. FAnusANns, C. D. MCVAY. 

